Deck 54: Concentration and Dilution of Urine

Question 1

The absorption of an isosmotic fluid in the proximal tubule occurs because

A) W ater follo w s so lute tran sp ort b y os m os is
B) W ater is actively transported
C) Salt is passively reabsorbed
D) Glucose is passively reabsorbed
E) Urea is passively reabsorbed

Answer 1

A

Question 2

The m ec ha nis m ind ire ctly r es po ns ible for ab so rp tion of s olu te a nd wa ter in th e p ro xim al tu bu le is

A) SGLT1
B) GLUT2
C) NCX
D) NHE
E) Na-K-ATPase

Answer 2

E

Question 3

The fluid entering the distal tubule from the loop of Henle

A) Is hypoosmotic to plasma
B) H as the sa m e v olu m e a s f luid tha t en ter s th e lo op of H en le
C) H as all th e u re a th at w as pre se nt a t the en d o f th e p ro xim al tu bu le
D) Has the same creatinine concentration as the fluid that enters the loop of Henle because creatinine is not reabsorbed in the loop
E) Is in osmotic equilibrium with the kidney interstitium

Answer 3

A

Question 4

The early distal tubule is distinct from the late distal tubule in that

A) It is not permeable to water
B) It reabsorbs Na and Cl thorugh the Na-K-2Cl cotransporter
C) It is not sensitive to ADH
D) It does not reabsorb Na and Cl
E) Both A and C are true

Question 5

Pla sm a g luc os e th at e xc ee ds the ren al th re sh old

A) Means the Tm for glucose is decreased
B) Is a consequence of osmotic equilibration
C) Incr eas es u rine flow by o sm otic diu resis
D) Is r ea bs or be d c om ple tely in the pro xim al tu bu le
E) Is r ea bs or be d e ve ntu ally in the dis tal tu bu le

Question 6

The limit for excretion of dilute urine is about

A) 600 mO sM
B) 300 mO sM
C) 150 mO sM
D) 70 mOsM
E) 20 mO sM

Question 7

The co nc en tra tion or d ilutio n o f ur ine is c on tro lled by a ho rm on e, w hic h is

A) Aldosterone
B) R en in
C) An gio ten sin
D) ADH
E) Epinephrine

Question 8

Blood in the aggregate efferent arterioles

A) Is hypoosmotic due to glomerular filtration
B) Has a higher oncotic pressure than systemic blood
C) Mainly perfuses the kidney interstitium
D) Has a higher hydrostatic pressure than afferent arteriolar blood
E) Has a lower oncotic pressure than afferent ateriolar blood

Question 9

In the absence of ADH

A) Urine flow is high an d urine is dilute
B) Urea permeability in the collecting duct is high
C) W ater permeability in the late distal tubule is high
D) T he pro xim al tu bu le re ab so rb s m or e s alt
E) Both A and C are true

Question 10

The limit for excretion of concentrated urine is about

A) 3000 mO sM
B) 2000 mO sM
C) 1200 mOsM
D) 600 mO sM
E) 300 mO sM

Question 11

The osm otic gradient in the outer medullary interstitium is mainly caused by

A) NaCl
B) Urea
C) Glucose
D) KCl E proteins

Question 12

Infusion of mannitol

A) Marks the extracellular fluid volume
B) Increases the final osmolarity of the urine
C) Increases the osmolarity of the kindey interstitium
D) Increases urine flow
E) Increases renal plasma flow

Question 13

The part of the kidney that acts as a counter-current multiplier is the

A) Pr ox im al tu bu le
B) Lo op of H en le
C) Ea rly dis tal tu bu le
D) Va sa R ecta
E) Collecting duct

Question 14

The Increase in os m otic gra die nt in the inn er m ed ulla ry int er stitiu m co m pa re d to the ou ter m ed ulla is mainly caused by

A) NaCl
B) Urea
C) Glucose
D) KCl E proteins

Question 15

At the end of the proximal tubule, tubule fluid osmolarity is about

A) 600 mO sM
B) 300 mOsM
C) 100 mO sM
D) 70 mO sM
E) 1200 mO sM

Question 16

The part of the kidney that acts as a counter-current exchanger is the

A) Pr ox im al tu bu le
B) Lo op of H en le
C) Ea rly dis tal tu bu le
D) Vasa R ecta
E) Collecting duct

Question 17

The fluid no rm ally p re se nte d to the loo p o f H en le fr om the pro xim al tu bu le

A) Is isosmotic with plasma
B) Has no glucose
C) Has no amino acids
D) Has had two-thirds of Na+ reabsorbed
E) All of the above are true

Question 18

The thick ascending limb of Henle reabsorbs Na+ and Cl-

A) Via a amiloride-sensitive EnaC
B) Via a thiazide-sensitive Na-Cl cotransporter
C) Via a furosemide-sensitive Na-K-2Cl cotransporter
D) Via AQP2
E) Via AQP4

Question 19

In the presence of high ADH

A) Urin e flow is high and urine is dilute
B) Urine flow is high and urine is concentrated
C) Urin e flow is low a nd u rine is d ilute
D) Urine flow is low and urine is concentrated
E) Urine flow stops

Question 20

The Lo op of H en le

A) D oe s n ot r ea bs or b w ate r or sa lt
B) R ea bs or bs wa ter in e xc es s o f s alt
C) Reabsorbs salt in excess of water
D) Reabsorbs salt and water in equal proportions
E) Reabsorbs salt and water into the peritubular capillaries

Question 21

The highest concentration reached in the inner medullary interstitium is about

A) 300 mO sM
B) 600 mO sM
C) 900 mO sM
D) 1200 mOsM
E) 1500 mO sM

Question 22

The blo od in th e v as a re cta tha t lea ve s th e m ed ulla is

A) Slig htly h ypo os m otic
B) Slig htly h ype ros m otic
C) H igh ly hyp oo sm otic
D) H igh ly hyp er os m otic
E) Iso sm otic